Data SIMs in Japan don't pick up 3G network


I’m using a Fairphone FP1U. I’m in Japan right now and purchased a data only SIM card, given the fact that you need to be a resident in order to get a full-blown SIM.

Problem is, it doesen’t pick up the Docomo 3G network, i.e. the network bar shows a red X. The SIM is recognised by the phone and when I search for networks I can actually see that the phone finds “Docomo 3G” and “Softbank 3G (forbidden)”. When I try to manually connect to Docomo, it gives me the error message “can’t connect to this network right now. please try again later”.

The APN settings are correct and I tried to reboot the phone, switched on and off the flight mode, changed SIM slots, changed the 3G settings for SIMs. Nothing, no connection to the internet. The local support gave me some troubleshooting, but that didn’t work. They also mentioned that some phones don’t show network connectivity, but are connected anyway. But that’s not the case either.

In a similar topic (Fairphone Use in Japan bmobile visitor sim doesnt work) a user reports that bmobile sims don’t works with the Fairphone, and I seem to have a similar issue here. Bmobile also uses the Docomo 3G network. I tried comst Tsim ( and Yamada SIM which is based on a service run by umobile ( Both use Docomo 3G.

The topic is closed with the conclusion that “It is not possible to use the Fairphone on the Japan bmobile network as the Fairphone does not support the LTE/4G networks that the network is using.” It is correct that the Fairphone does not support LTE/4G, but it should in any case pick up 3G.

Data SIMs in Japan support both LTE/4G and 3G connections. 3G uses Band 1 (2100 MHz) which is supported by the Fairphone. I made the test and put in another Japanese SIM card from Softbank (a prepaid one that supports calls and SMS, no data). This one picks up the Softbank 3G. Another SIM that I have been using in Sweden also works without problems in Japan. It even gives me the choice to manually select either Softbank 3G or Docomo 3G. Both give me connectivity.

So, to summarise, the Fairphone, by default, does support Japanese 3G. There seems to be an issue concerning registration on the Docomo 3G network with data-only SIMs. I just can’t figure out what it might me. Other non-Japanese phones seem to work flawlessly, except some Samsung models, according to the guy in the mobile shop.

This is mainly to report the issue to prospective Japan-travellers.
Also any ideas on how to fix this are appreciated! Thanks!


Hm, this sounds like we should flag this up to Fairphone support, to hand this down to the tech departement.


Did you try leaving one of the above cards in first slot (e. g. the swedish one), inserting the JP-3G-only SIM in the second slot, and then updating the setting asking for data connections to be used through card 2 (or whatever its name)?
I remember there were various ways of setting things wrong on this issue (I also use two sims, of which the second one is data only, and spent some hours before finding the right setup).
At least, but I may not remember everything, within the SIM ifo setup, where you see both SIMcards at the top, you must have something like

  • vocal call = swedish SIM (even if you don’t use it)
  • video call = JP SIM
  • SMS = swedish
  • data = JP SIM

Thanks for the suggestion. I did as you said, i.e. Swedish SIM Slot 1, Japanese data-only SIM Slot 2 and updated the preferences for data connection etc, but it didn’t give me connectivity. By the way, Japan has no 2G network which makes the Dual-SIM function less useful, as it’s always only one of the SIMs that can be assigned to 3G.

This is the message I get when I try to manually connect to Docomo 3G with the Japanese data-only SIM inserted. Would be helpful to see the details. Is there any way to get more info out of the device concerning the error?

Update: My workaround of the issue is the following.

I researched a bit on the internet about sim-free mobile wi-fi routers and found some places in Akihabara, Tokyo, where they sell used ones. I bought a Huawei GL01P, originally thrown onto the market by Emobile (doesn’t exist any more tho) in 2012, for 3500 Yen. Most Huawei devices are sim-free by default (except for GL09P and GL10P), plus it is possible to get a Docomo router and have it unlocked at a Docomo store for a fee. According to my research GLxxP line devices are quite reliable and work with all kinds of SIMs. Can also be used outside Japan (all depends on the network bandwidth regulations in each country tho).

As most data-only SIMs rely on the NTT Docomo network, it it important to check whether the bandwidths of the router and the network that the SIM can pick up match. In my case I was told that the (former) Emobile LTE network and the Docomo LTE network don’t match, whereas the respective 3G networks do, so 3G only. But fortunately NTT Docomo just opened up (March 2015) a new band for LTE that miraculously matches the former Emobile LTE network. So all good.

Suggestion to prospective travellers to Japan: Take with you your old smartphone lying around at home, get a data-sim and tether it to your Fairphone. In case you already are in Japan: get a sim-free wi-fi router.